Quantitative secondary ion mass spectrometry analysis of impurities in GaN and Al Ga N films using molecular ions x 1yx MCsq and MCsq2

In SIMS analysis of GaN and Al Ga N films, MCsqand MCsqion detection M is the element to be analyzed.was x 1yx 2 investigated under Csq bombardment. The MCsq2 ions have a larger ion yield than the MCsq ions when M is one of electronegative ions. Application of these molecular ions to SIMS analysis has made it possible to detect electropositive and electronegative elements in a single analysis run. Further, these molecular ions are useful to minimize the matrix effect in Al Ga N films, with x ranging from 0 to 0.17. The formation mechanism of the MCsq and MCsq ions can also be x 1yx 2 postulated by comparing the useful yield of these molecular ions and that of single negative andror positive.ions. These molecular ions are assumed to be produced mainly by recombination processes in which sputtered neutral species M andror MCs. combine with Csq ions. q1999 Elsevier Science B.V. All rights reserved